core: clean up split-lines with subseq-as. clean up subseq/subseq-as/subseq-unsafe/subseq-unsafe-as.

core/sequences/sequences-docs.factor

@@ -990,6 +990,11 @@ HELP: subseq
 { $description "Outputs a new sequence consisting of all elements starting from and including " { $snippet "from" } ", and up to but not including " { $snippet "to" } "." }
 { $errors "Throws an error if " { $snippet "from" } " or " { $snippet "to" } " is out of bounds." } ;
 
+HELP: subseq-as
+{ $values { "from" "a non-negative integer" } { "to" "a non-negative integer" } { "seq" sequence } { "exemplar" sequence } { "subseq" "a new sequence" } }
+{ $description "Outputs a new sequence consisting of all elements starting from and including " { $snippet "from" } ", and up to but not including " { $snippet "to" } " of type " { $snippet "exemplar" } "." }
+{ $errors "Throws an error if " { $snippet "from" } " or " { $snippet "to" } " is out of bounds." } ;
+
 HELP: clone-like
 { $values { "seq" sequence } { "exemplar" sequence } { "newseq" "a new sequence" } }
 { $description "Outputs a newly-allocated sequence with the same elements as " { $snippet "seq" } " but of the same type as " { $snippet "exemplar" } "." }
@@ -1737,6 +1742,7 @@ $nl
 "Extracting a subsequence:"
 { $subsections
     subseq
+    subseq-as
     head
     tail
     head*

core/sequences/sequences.factor

@@ -313,13 +313,19 @@ C: <copy> copy-state
 : copy-unsafe ( src i dst -- )
     [ [ length check-length 0 ] keep ] 2dip <copy> (copy) drop ; inline
 
+: subseq-unsafe-as ( from to seq exemplar -- subseq )
+    [ subseq>copy (copy) ] dip like ;
+
 : subseq-unsafe ( from to seq -- subseq )
-    [ subseq>copy (copy) ] keep like ;
+    dup subseq-unsafe-as ; inline
 
 PRIVATE>
 
+: subseq-as ( from to seq exemplar -- subseq )
+    [ check-slice ] dip subseq-unsafe-as ;
+
 : subseq ( from to seq -- subseq )
-    [ check-slice subseq>copy (copy) ] keep like ;
+    dup subseq-as ; inline
 
 : head ( seq n -- headseq ) (head) subseq ;
 

core/splitting/splitting.factor

@@ -106,16 +106,12 @@ PRIVATE>
         [ pick subseq ] keep swap
     ] map 2nip ;
 
-GENERIC: string-lines ( str -- seq )
+: string-lines ( seq -- seq' )
-
-M: string string-lines
     [ V{ } clone 0 ] dip [ 2dup bounds-check? ] [
         2dup [ "\r\n" member? ] find-from swapd [
             over [ [ nip length ] keep ] unless
-            [ subseq suffix! ] 2keep [ 1 + ] dip
+            [ "" subseq-as suffix! ] 2keep [ 1 + ] dip
         ] dip CHAR: \r eq? [
             2dup ?nth CHAR: \n eq? [ [ 1 + ] dip ] when
         ] when
     ] while 2drop { } like ;
-
-M: sbuf string-lines "" like string-lines ;

extra/sequences/extras/extras.factor

@@ -51,9 +51,6 @@ IN: sequences.extras
         ] each
     ] each ; inline
 
-: subseq-as ( from to seq exemplar -- subseq )
-    [ check-slice subseq>copy (copy) ] dip like ;
-
 : map-like ( seq exemplar -- seq' )
     '[ _ like ] map ; inline